1. Field of the Invention
The present invention relates to the manipulation of computer generated images on a display, and more particularly, to a method and apparatus for interactive cropping that eliminates the distractions associated with the conventional image cropping technique.
2. Discussion of the Related Art
In the processing of photographic or photorealistic images, users often wish to exclude portions of the image. This operation is called cropping. Conventional methods for cropping allow some or all of the excluded portion of the image to remain visible during the selection of the area to be included. The excluded portion of the image distracts the user and makes it more difficult to visualize the cropped image.
In digital image processing, the user selects a portion of an image and discards the rest by controlling the position and size of a rectangle with a manual pointing device such as a mouse. The conventional cropping technique executed by software image editors requires the user to indicate the boundaries of the new image by a thin border applied over the original image. In this presentation, the part of the original image that is outside the area of the new image serves as a distraction to the user, sometimes preventing proper visualization of the aesthetics of the new image. When the software program is commanded to complete the cropping, the new image is finally visible without the distractions, but it is time consuming for the user to go back and re-crop. In addition, because the user cannot easily compare the effects of similar but non-identical cropping boundaries, the best cropping for the application can easily be overlooked.
U.S. Pat. No. 4,603,966 of Brownstein discloses a system for cropping photographs. A solid state sensor is used to create an electronic image of the photograph which is displayed on a video monitor. A zoom lens allows for magnification, an X-Y translation stage moves the film vertically and horizontally, and a rotatable table allows for selective rotation of the film about a centerline. A horizontal or vertical rectangular reticile is displayed on the video monitor and the portion of the image within the reticile can be printed as shown. The portion outside the reticile can be "blanked out" by depressing the print button. The system of the Brownstein patent is similar to the conventional cropping technique executed by software image editors in that only the final cropped image is displayed when the excluded portion is "blanked out". While the is distraction of the excluded portion of the image is removed, the user must restore the entire original image to evaluate whether re-cropping would improve the final product.